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                回忆树                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：256MB</p>			</div>
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                                <h3>题目描述</h3><p><div>回忆树是树。</div>
<div>具体来说，是n个点n-1条边的无向连通图，点标号为1~n，每条边上有一个字符（出于简化目的，我们认为只有小写字母）。</div>
<div>对一棵回忆树来说，回忆当然是少不了的。</div>
<div>一次回忆是这样的：你想起过往，触及心底&hellip;唔,不对，我们要说题目。</div>
<div>这题中我们认为回忆是这样的：给定2个点u，v(u可能等于v)和一个非空字符串s，问从u到v的简单路径上的所有边按照到u的距离从小到大的顺序排列后，边上的字符依次拼接形成的字符串中给定的串s出现了多少次。</div>
<p></p></p><hr/><h3>输入格式</h3><p><div>第一行2个整数，依次为树中点的个数n和回忆的次数m。</div>
<div>接下来n-1行，每行2个整数u、v和1个小写字母c，表示回忆树的点u、v之间有一条边，边上的字符为c</div>
<div>接下来2m行表示m次回忆，每次回忆2行：第1行2个整数u、v，第2行给出回忆的字符串s。</div>
<p></p></p><hr/><h3>输出格式</h3><p><div>对于每次回忆，输出串s出现的次数。</div>
<p></p></p><hr/><h3>样例输入</h3><pre>12 3
1 2 w
2 3 w
3 4 x
4 5 w
5 6 w
6 7 x
7 8 w
8 9 w
9 10 x
10 11 w
11 12 w
1 7
wwx
1 12
www
1 12
w</pre><hr/><h3>样例输出</h3><pre>2
0
8</pre><hr/><h3>提示</h3><p><div>对于100%的数据，n&lt;=100000,m&lt;=100000,询问串的总长&lt;=300000</div>
<div></div>
<p></p></p><hr/><h3>题目来源</h3><p>没有写明来源</p>
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